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Add mesh comparison functions, for tests
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@numberZero @rubenwardy
numberZero authored and rubenwardy committed Feb 22, 2024
1 parent bf2098c commit 753f03f
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2 changes: 2 additions & 0 deletions src/unittest/CMakeLists.txt
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Expand Up @@ -42,9 +42,11 @@ set (UNITTEST_SRCS
PARENT_SCOPE)

set (UNITTEST_CLIENT_SRCS
${CMAKE_CURRENT_SOURCE_DIR}/mesh_compare.cpp
${CMAKE_CURRENT_SOURCE_DIR}/test_clientactiveobjectmgr.cpp
${CMAKE_CURRENT_SOURCE_DIR}/test_eventmanager.cpp
${CMAKE_CURRENT_SOURCE_DIR}/test_gameui.cpp
${CMAKE_CURRENT_SOURCE_DIR}/test_mesh_compare.cpp
${CMAKE_CURRENT_SOURCE_DIR}/test_keycode.cpp
PARENT_SCOPE)

103 changes: 103 additions & 0 deletions src/unittest/mesh_compare.cpp
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@@ -0,0 +1,103 @@
/*
Minetest
Copyright (C) 2023 Vitaliy Lobachevskiy
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include "mesh_compare.h"
#include <algorithm>
#include <map>
#include <stdexcept>

static std::vector<Triangle> expandMesh(const std::vector<video::S3DVertex> &vertices, const std::vector<u16> &indices)
{
const int n_indices = indices.size();
const int n_triangles = n_indices / 3;
if (n_indices % 3)
throw std::invalid_argument("got fractional number of triangles");

std::vector<Triangle> ret(n_triangles);
for (int i_triangle = 0; i_triangle < n_triangles; i_triangle++) {
ret.at(i_triangle) = {
vertices.at(indices.at(3 * i_triangle)),
vertices.at(indices.at(3 * i_triangle + 1)),
vertices.at(indices.at(3 * i_triangle + 2)),
};
}

return ret;
}

/// Sorts triangle vertices, keeping winding order.
static Triangle sortTriangle(Triangle t)
{
if (t[0] < t[1] && t[0] < t[2]) return {t[0], t[1], t[2]};
if (t[1] < t[2] && t[1] < t[0]) return {t[1], t[2], t[0]};
if (t[2] < t[0] && t[2] < t[1]) return {t[2], t[0], t[1]};
throw std::invalid_argument("got bad triangle");
}

static std::vector<Triangle> canonicalizeMesh(const std::vector<video::S3DVertex> &vertices, const std::vector<u16> &indices)
{
std::vector<Triangle> mesh = expandMesh(vertices, indices);
for (auto &triangle: mesh)
triangle = sortTriangle(triangle);
std::sort(std::begin(mesh), std::end(mesh));
return mesh;
}

bool checkMeshEqual(const std::vector<video::S3DVertex> &vertices, const std::vector<u16> &indices, const std::vector<Triangle> &expected)
{
auto actual = canonicalizeMesh(vertices, indices);
return actual == expected;
}

bool checkMeshEqual(const std::vector<video::S3DVertex> &vertices, const std::vector<u16> &indices, const std::vector<Quad> &expected)
{
using QuadRefCount = std::array<int, 4>;
struct QuadRef {
unsigned quad_id;
int quad_part;
};

std::vector<QuadRefCount> refs(expected.size());
std::map<Triangle, QuadRef> tris;
for (unsigned k = 0; k < expected.size(); k++) {
auto &&quad = expected[k];
// There are 2 ways to split a quad into two triangles. So for each quad,
// the mesh must contain either triangles 0 and 1, or triangles 2 and 3,
// from the following list. No more, no less.
tris.insert({sortTriangle({quad[0], quad[1], quad[2]}), {k, 0}});
tris.insert({sortTriangle({quad[0], quad[2], quad[3]}), {k, 1}});
tris.insert({sortTriangle({quad[0], quad[1], quad[3]}), {k, 2}});
tris.insert({sortTriangle({quad[1], quad[2], quad[3]}), {k, 3}});
}

auto actual = canonicalizeMesh(vertices, indices);
for (auto &&tri: actual) {
auto itri = tris.find(tri);
if (itri == tris.end())
return false;
refs[itri->second.quad_id][itri->second.quad_part] += 1;
}

for (unsigned k = 0; k < expected.size(); k++) {
if (refs[k] != QuadRefCount{1, 1, 0, 0} && refs[k] != QuadRefCount{0, 0, 1, 1})
return false;
}

return true;
}
47 changes: 47 additions & 0 deletions src/unittest/mesh_compare.h
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@@ -0,0 +1,47 @@
/*
Minetest
Copyright (C) 2023 Vitaliy Lobachevskiy
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#pragma once
#include <array>
#include <vector>
#include <irrlichttypes.h>
#include <S3DVertex.h>

/// Represents a triangle as three vertices.
/// “Smallest” (according to <) vertex is expected to be first, others should follow in the counter-clockwise order.
using Triangle = std::array<video::S3DVertex, 3>;

/// Represents a quad as four vertices.
/// Vertices should be in the counter-clockwise order.
using Quad = std::array<video::S3DVertex, 4>;

/// Compare two meshes for equality.
/// @param vertices Vertices of the first mesh. Order doesn’t matter.
/// @param indices Indices of the first mesh. Triangle order doesn’t matter. Vertex order in a triangle only matters for winding.
/// @param expected The second mesh, in an expanded form. Must be sorted.
/// @returns Whether the two meshes are equal.
[[nodiscard]] bool checkMeshEqual(const std::vector<video::S3DVertex> &vertices, const std::vector<u16> &indices, const std::vector<Triangle> &expected);

/// Compare two meshes for equality.
/// @param vertices Vertices of the first mesh. Order doesn’t matter.
/// @param indices Indices of the first mesh. Triangle order doesn’t matter. Vertex order in a triangle only matters for winding.
/// @param expected The second mesh, in a quad form.
/// @returns Whether the two meshes are equal.
/// @note There are two ways to split a quad into 2 triangles; either is allowed.
[[nodiscard]] bool checkMeshEqual(const std::vector<video::S3DVertex> &vertices, const std::vector<u16> &indices, const std::vector<Quad> &expected);
152 changes: 152 additions & 0 deletions src/unittest/test_mesh_compare.cpp
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/*
Minetest
Copyright (C) 2023 Vitaliy Lobachevskiy
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include "test.h"

#include "mesh_compare.h"

// This is a self-test to ensure proper functionality of the vertex
// building functions (`Triangle`, `Quad`) and its validation function
// `checkMeshEqual` in preparation for the tests in test_content_mapblock.cpp
class TestMeshCompare : public TestBase {
public:
TestMeshCompare() { TestManager::registerTestModule(this); }
const char *getName() override { return "TestMeshCompare"; }

void runTests(IGameDef *gamedef) override {
TEST(testTriangle);
TEST(testQuad);
}

void testTriangle() {
UASSERT(checkMeshEqual({
{{1., 0., 0.}, {3., 0., 0.}, 1, {0., 0.}},
{{0., 1., 0.}, {2., 0., 0.}, 2, {0., 0.}},
{{0., 0., 1.}, {1., 0., 0.}, 3, {0., 0.}},
}, {0, 1, 2}, {
Triangle{{
{{0., 0., 1.}, {1., 0., 0.}, 3, {0., 0.}},
{{1., 0., 0.}, {3., 0., 0.}, 1, {0., 0.}},
{{0., 1., 0.}, {2., 0., 0.}, 2, {0., 0.}},
}},
}));
UASSERT(checkMeshEqual({
{{1., 0., 0.}, {3., 0., 0.}, 1, {0., 0.}},
{{0., 1., 0.}, {2., 0., 0.}, 2, {0., 0.}},
{{0., 0., 1.}, {1., 0., 0.}, 3, {0., 0.}},
}, {2, 0, 1}, {
Triangle{{
{{0., 0., 1.}, {1., 0., 0.}, 3, {0., 0.}},
{{1., 0., 0.}, {3., 0., 0.}, 1, {0., 0.}},
{{0., 1., 0.}, {2., 0., 0.}, 2, {0., 0.}},
}},
}));
UASSERT(!checkMeshEqual({
{{1., 0., 0.}, {3., 0., 0.}, 1, {0., 0.}},
{{0., 1., 0.}, {2., 0., 0.}, 2, {0., 0.}},
{{0., 0., 1.}, {1., 0., 0.}, 3, {0., 0.}},
}, {0, 2, 1}, {
Triangle{{
{{0., 0., 1.}, {1., 0., 0.}, 3, {0., 0.}},
{{1., 0., 0.}, {3., 0., 0.}, 1, {0., 0.}},
{{0., 1., 0.}, {2., 0., 0.}, 2, {0., 0.}},
}},
}));

UASSERT(checkMeshEqual({
{{0., 0., 1.}, {1., 0., 0.}, 3, {0., 0.}},
{{0., 1., 0.}, {2., 0., 0.}, 2, {0., 0.}},
{{1., 0., 0.}, {3., 0., 0.}, 1, {0., 0.}},
}, {0, 1, 2}, {
Triangle{{
{{0., 0., 1.}, {1., 0., 0.}, 3, {0., 0.}},
{{0., 1., 0.}, {2., 0., 0.}, 2, {0., 0.}},
{{1., 0., 0.}, {3., 0., 0.}, 1, {0., 0.}},
}},
}));
UASSERT(!checkMeshEqual({
{{1., 0., 0.}, {3., 0., 0.}, 1, {0., 0.}},
{{0., 1., 0.}, {2., 0., 0.}, 2, {0., 0.}},
{{0., 0., 1.}, {1., 0., 0.}, 3, {0., 0.}},
}, {0, 1, 2}, {
Triangle{{
{{0., 0., 1.}, {1., 0., 0.}, 3, {0., 0.}},
{{0., 1., 0.}, {2., 0., 0.}, 2, {0., 0.}},
{{1., 0., 0.}, {3., 0., 0.}, 1, {0., 0.}},
}},
}));
}

void testQuad() {
UASSERT(checkMeshEqual({
{{1., 0., 0.}, {3., 0., 0.}, 1, {0., 0.}},
{{0., 1., 0.}, {2., 0., 0.}, 2, {0., 0.}},
{{0., 0., 1.}, {1., 0., 0.}, 3, {0., 0.}},
{{1., -1., 1.}, {4., 0., 0.}, 4, {0., 0.}},
}, {0, 1, 2, 0, 2, 3}, {
Quad{{
{{1., 0., 0.}, {3., 0., 0.}, 1, {0., 0.}},
{{0., 1., 0.}, {2., 0., 0.}, 2, {0., 0.}},
{{0., 0., 1.}, {1., 0., 0.}, 3, {0., 0.}},
{{1., -1., 1.}, {4., 0., 0.}, 4, {0., 0.}},
}},
}));
UASSERT(checkMeshEqual({
{{1., 0., 0.}, {3., 0., 0.}, 1, {0., 0.}},
{{0., 1., 0.}, {2., 0., 0.}, 2, {0., 0.}},
{{0., 0., 1.}, {1., 0., 0.}, 3, {0., 0.}},
{{1., -1., 1.}, {4., 0., 0.}, 4, {0., 0.}},
}, {2, 3, 0, 1, 2, 0}, {
Quad{{
{{1., 0., 0.}, {3., 0., 0.}, 1, {0., 0.}},
{{0., 1., 0.}, {2., 0., 0.}, 2, {0., 0.}},
{{0., 0., 1.}, {1., 0., 0.}, 3, {0., 0.}},
{{1., -1., 1.}, {4., 0., 0.}, 4, {0., 0.}},
}},
}));
UASSERT(checkMeshEqual({
{{1., 0., 0.}, {3., 0., 0.}, 1, {0., 0.}},
{{0., 1., 0.}, {2., 0., 0.}, 2, {0., 0.}},
{{0., 0., 1.}, {1., 0., 0.}, 3, {0., 0.}},
{{1., -1., 1.}, {4., 0., 0.}, 4, {0., 0.}},
}, {2, 3, 1, 0, 1, 3}, {
Quad{{
{{1., 0., 0.}, {3., 0., 0.}, 1, {0., 0.}},
{{0., 1., 0.}, {2., 0., 0.}, 2, {0., 0.}},
{{0., 0., 1.}, {1., 0., 0.}, 3, {0., 0.}},
{{1., -1., 1.}, {4., 0., 0.}, 4, {0., 0.}},
}},
}));
UASSERT(checkMeshEqual({
{{1., 0., 0.}, {3., 0., 0.}, 1, {0., 0.}},
{{0., 1., 0.}, {2., 0., 0.}, 2, {0., 0.}},
{{0., 0., 1.}, {1., 0., 0.}, 3, {0., 0.}},
{{1., -1., 1.}, {4., 0., 0.}, 4, {0., 0.}},
}, {3, 0, 1, 1, 2, 3}, {
Quad{{
{{1., 0., 0.}, {3., 0., 0.}, 1, {0., 0.}},
{{0., 1., 0.}, {2., 0., 0.}, 2, {0., 0.}},
{{0., 0., 1.}, {1., 0., 0.}, 3, {0., 0.}},
{{1., -1., 1.}, {4., 0., 0.}, 4, {0., 0.}},
}},
}));
}
};

static TestMeshCompare mesh_compare_test;

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